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Adding steam radiator

David_54 Member Posts: 16
edited January 2017 in Strictly Steam
Hi there. I have a master bedroom to which I would like to a add a larger radiator in a better location. I have plenty of steam capacity. I have a Trane two pipe system, WM EG-25, runs at about 2 oz pressure, works well. I would disconnect existing undersized bedroom rad from basement mains (left as undersized from remodel decades ago) I would like to locate the new rad under the largest window in the room. Need to run piping down exterior wall. Does piping need to be large diameter >=3/4" iron or are there other alternatives. I'm thinking baseboard or something low profile (not thick). A large, freestanding rad would not be a good fit aesthetically in this particular room. Any suggestions on piping, rads or baseboard?


  • MilanD
    MilanD Member Posts: 1,160
    edited January 2017
    2 thoughts, from a steam user/maintenance person in a large building, with some short and some long rad risers

    If all runs are to all the rest of the rads is 3/4, and this new rad will not be on a fairly same lenght of pipe as the other rads, 3/4 will be fine. You should be able to vent it to get equal amount of steam to it.

    The only other thing you may have to do is rebalance the rest of the rads. But, it's 2 pipe are running at 2 oz, so I think you won't have to do anything.

    If this room is too cold as is, you may bump the pipe size to 1". This will "steal" steam from the main first, and this rad will now definitely get the steam 1st.
    EBEBRATT-Ed Member Posts: 15,344
    I would go on the Burnham website (US Boiler) and look under radiation for what is available.

    You can use a radiator, or convector or Base Ray CI baseboard. First you should do a heat loss of the room so you know how much radiation to install.

    You should also try and determine how your existing radiation in the rest of the house is sized. If its 10% oversized for instance then you would size your new radiator the same way. Otherwise the house will not balance.

    Once you know the capacity of the new radiation come back here and we can help with pipe sizing and venting
  • David_54
    David_54 Member Posts: 16
    edited January 2017
    For the most part, the rest of the house is oversized, rads left over from the coal-fired days of the 1920s. None of my rads ever get 100% hot before the thermostat is satisfied. I'm in Michigan. Rumor has it that it was considered healthy to leave windows partially open during the winter for fresh air (No one realized the rest of the housing envelope leaked like a sieve letting in plenty of makeup air). Thus the coal boiler steamed 24/7 during the heating season - the rads must have been more completely hot back then. Fast forward to 2017, with new windows, insulation, etc. my existing rads are larger than they need to be.